FileNotFound exception with RandomAccessFile using Path obtained from WatchService?

Question

Why would obtaining a RandomAccessFile(path.toFile(),"rw") produce a FileNotFoundException from a Path that was returned from WatchService and the WatchEvent kind is ENTRY_CREATE?

java.io.FileNotFoundException: 
C:\SharedFolders\FromS01\SSLServer01\SSLInternal02\DOMAIN\EML\E6046292.723
(The process cannot access the file because it is being used by another process)
    at java.io.RandomAccessFile.open(Native Method) ~[na:1.8.0-ea]
    at java.io.RandomAccessFile.<init>(RandomAccessFile.java:236) ~[na:1.8.0-ea]
    at cbbb.filejobs.Main.fileCopied(Main.java:446) ~[CbbbFileJobs.jar:na]
    at cbbb.filejobs.Main.processFilesPending(Main.java:409) ~[CbbbFileJobs.jar:na]
    at cbbb.filejobs.Main.handleFileTasks(Main.java:156) ~[CbbbFileJobs.jar:na]

Answer 1

"The process cannot access the file because it is being used by another process"

It turns out that with a WatchService event, the file is not necessarily usable the instant it is created.

Sometimes the operating system has the file status in an intermediate state the moment it has a file create event.

The solution, in my case, is to:

1) Watch for the MODIFIED event. All files with content will have a CREATED followed by a MODIFIED.

2) Check that the file exists again (in case it was DELETED immediately after CREATED). And then retry to get a RandomAccessFile on it. This never happened but I suppose it could -theoretically.

3) If the file was deposited using operating system exclusive/shared locking. Then the lock will not be obtainable if the other process still has a handle on it.

What is funny .... buggy actually .. is that I was previously able to LOCK the file exclusive (and shared worked) when it was just CREATED. But the file content was always null.

So, it seems that LOCKING immediately after CREATE does not always work. Waiting for MODIFIED before trying to lock seems to solve the problem.

Really, the exception should not be FileNotFound, ,but FileInUse or FileNotAccessible ...